Lubricant pump



, 2,886,135 Patented May 12,1959

This.invention'r elates to a lubricant pump of that type in which one orseveral pump units are separately inserted in apump box and each of saidpump units comprises .a

cylinder and a working piston, which is formed with one or severalcontrol ports and; is rotatable to control the .connectionof its workingspace with the inlet and outlet. Inthe known pumps of that type in whichthe pump units are individually inserted in the pump box, these unitsare flanged. to the pump box from the outside. Such constructions aresomewhat. less expensive than constructions in which groups of pumpunits are combined to form a block and inserted in the pump box becausethe pump units for pumps having different numbersof outlets can bemanufactured in larger quantities. constructions, howeven the economy{thus effected is not r t e au e u h Pump units n d t the P mp casingare of relatively complicated shape and require expensive machiningoperations.

It is an object of the. invention to reduce the cost of such lubricantpumps. The invention is based on the recognition thata considerablesimplification in construc- In the known length is reduced and thebosses which must be provided in the pump box casting to accommodate thebores receiving the cylinders may be relatively small. In order to avoida disturbance of the simple shape enabled by the invention the meansrequired in that type of pumpto prevent the rotation of the cylinder andto determine its inserted position may comprise a detachable part, e. g.a pin inserted in the cylinder and engaging a groove inthe bore of thepump box, or a ledge aflixed to the pump box and cooperating with asurfaceformed on the cylinder, so that neither the outside surface ofthe cylinder nor the bore of the pump box has a projecting part whichwould considerably add to the machining expense.

Illustrative embodiments of the invention are shown in the drawing. 1

Fig. 1 is a sectional view of the pump box and a pump unit of alubricating pump. 1

Fig. 2 is a sectional view of the pump box and a pump unit of alubricant pump of modified construction. 1

In the embodiment according to Fig. 1, 1 represents thepump box,whichhas inserted therein the pump units comprising a cylinder 2 and apiston 3. The piston 3 is driven in theusual manner by a ball pin 6 of atappet rod 7, which isrotatably and axially slidably mounted and isdriven to oscillate and axially reciprocate through theintermediary of ahall pin 8, which engages an eccentric bore 9 of a head 10 of thedriveshaft 11. The ball' pin 6 enters a cavity 4 of the piston head 5. Thusthe piston 3 does not only perform a reciprocating conveyingmovementubut. also a rotary control movement, in the tion is possiblejust in that type of lubricant pumps in ,whicl xthe control olj theworking spaceis effectedfiby the rotation of the working piston and inwhich for that rea son only a single piston and one cylinder arerequired for each valveless pump unit. The invention resides essenofrevolution which is or conical shape or provided with t a collar in itsintermediate zone and which is held against rotation and is clamped byan outlet nipple in a bore which is reduced in conical or stepped form,whereas the intake duct which opens on the outside surface of thecylinder portion facing the interior of the casing is sealed from thedischarge duct which opens adjacent to the closed cylinder end andleads. into the cavity of said outlet nipple. The formation of thecylinder as a solid of revolution represents the simplest form, which isleast expensive as regards machining. This is due tothe elimination ofthe fixing flange for the pump unit and by the provision of a fixingmember, i.e. the screw nipple, which is separate from the cylinder. Theplace where the pump unit is received in the pump box consists only of abore, which is formed at its inner end with a constriction delimitingthe depth of insertion of the cylinder, and at its outer end, e.g., witha thread for the nipple. Thus the machining of the pump box is minimizedtoo. The measure of forming the bore of the pump box for the cylinderwith a conical reduction has the advantage compared to the steppedformation, that the cylinder is tightly forced into the outer cone bythe nipple and additional sealing members are eliminated. Thatconstruction is favourable if the inlet bore of the cylinder is to betightly sealed against course ofwhich itconnects its working space, 14in the known manner alternatelywiththe inlet bore 12 and the outlet bore13. 15 represents the setting screw which determines thequantity to bedelivered. V

1 The cylinder 2 is formed as a simple solid of revolution, which isprovid ed with a collar 16 in its intermediateaone. That cylinder isinserted in a bore 17 of thefpurnp, box :1 and is clamped by the outletnipple 18 agains t a shouldei 19 of the bore 17. Since a rotary pistonepntrol is employed, the cylinder 2 must be built in and securedginapredetermined position. ;T o this end the cylinder has inserted thereina pin 20, which engages a groove 21 of the bore of the shoulder 19. Inthe corresponding control position of the piston 3 the lubricant issucked from the interior 23 of the pump box 1 through a bore 22 of thepump box 1 and. the inlet bore 12 into the working space 14.

As the piston 3 is rotated its control groove 24 is connected to theoutlet bore 13 so that the piston 3 conveys the lubricant into theoutlet nipple 18. To this end the outlet bore 13 leads to a cavity 25 ofthe outlet nipple 18. As is shown in the drawing the outlet nipple 18 isformed at its inner end as a hollow cylinder 26, which has an externalscrew thread 27. Thus the cylinder 2 lies partly in the outlet nipple18, so that the overall length and the length of the bosses 28, 2'18provided in the pump box casting can be reduced. A gasket ring 29 isprovided between the hollow-cylindrical extension 26 i let nipple 18 andthe cylinder 2 as well as between the said parts and the bore 17. Noseal is required between the collar 16 of thecylinder 2 and the shoulder19 of the bore 17 because the pump unit sucks the lubricant directlyfrom the interior 23 of the pump box 1.

embodiment according to Fig. 1 mainly by the fact that The embodimentaccording to Fig. 2 differs from the the upper portion of the cylinder2' is formed with an external cone 30, which is forced into a conicalbore 31 of the casing. The cylinder 2 is again clamped in the pump box1' by the outlet nipple 18 and the outlet bore 1'8. Contraryto theconstruction according-to'Fig. 1-the rotation of the cylinder isprevented by a ledge 32 screwed to the pump box If and cooperating witha surface 33 formed-on the cylinder 2.

ln this case the supply of the lubricant vto the inlet bore 12 of thecylinder 2-'i s not efiected-directly'from the interior 23 f thepump-box -1"butthe-lubricantis sucked duringthe intake stroke of thepiston 3 through a riser 34, a sight glass 35 and a bore'36 into theworking-space 14 of the piston 3. For this reason this'embodimentrequires a seal between that portion of the periphery of the cylinder inwhich 'the suction line 12 opens and the interior 23 of the pumpbox;that seal-.is provided by the conical formation of the cylinder and ofthe bore 31.

This eliminatesthe need -for inserting an additional sealing member, thecompressibility of which would render the depth of insertion of thecylinder 2 indefinite and prevent an accurate setting of the quantitytobe delivered.

I claim: 7

1. .A lubricant .pump comprising a pmmpbox, a bore in said pump box, avalveless pump unit inserted in said bore, said pumpunitcomprising apump-icylinder and a piston reciprocating within the said pump cylinderand a working space in the said pump cylinder, an inlet opening and anoutlet opening in the outer surface of the said pump cylinder in axialdistance from each other, means for swinging the said piston aboutits'axis, means in the said piston for establishing communicationbetween the said working chamber and the said inlet opening and outletopening, respectively, when swung into its respective swing positions,the said pump cylinderbeing formed as a body of revolution, anoutlet-nipple coaxialWith-the said piston and pump cylinder clamping-thesaid pump cylinder in the said bore, the said outlet nipple having acavity, and means for preventing rotational movement of the said pumpcylinder in the said bore, sealing -means in the middle zone of saidbore and pump cylinder efiecting a tight seal between said bore and pumpcylinder, the said inlet opening being arranged in the part of *thesaidpump cylinder directed inwardly to the said pump box, the said outletopening being arranged in the outer part of the said pump cylinder andbeing in communication with the said cavity, the said sealing meansbeing arranged between the said inlet opening and outlet'opening andseparatin the said inletopening from the-said outlet opening.

2. In a lubricant pump as claimed in claim 1, a step in "the outer"surface of the said pump cylinder *and "a step in the said bore, thesaid outlet nipple clamping the said first-mentioned step against'thesecond-mentioned step.

3. In a lubricant pump as claimed in claim 1, a collar in the outersurface of the said pump cylinder and a step in the said bore, the saidoutlet nipple acting on the said collar and clamping the said collaragainst the said step, the said sealing means constituted by a packingarranged between the said outlet.nippleandthe:said collar.

4. In a lubricantpump as claimed in claim 1, the said pump cylinderhaving a conical. outer surface converging to its inner endand the saidbore being conical converted to the interior of the said pump box, theconicalsurfaces forming the said sealing means.

5. In a lubricant pump as claimed in claim 1, the said means forpreventing rotational movement of the said cylinder comprising adetachable part.

6. In a lubricant-pump'as claimed-in "claim 1,""a*pin inserted -in'-thesaid pump cylinder-and martial-groove in the said bore, the said-pinengaging the -said groove and "forming the said means for preventing-rotational movement'of that pump cylinder. p

7. -In a lubricant-pump asclaim'edin'claim l, 'a ledge fixed: onthe-said pump box and a flat surface formed-on theouter surface-ofthesaid pump cylinder, "cooperating with -the said ledge, 'the said ledgeand "flat surface "forming the said --means for preventing rotationalmovement of thesaid' pump cylinder.

8. .In 'a lubricant pump as-claimed in claim -1,.1ariser connectingthe-"interior of saidpump'box to the saiddfilet opening and means forsealing'the 'surface' -zone of the said cylinder which contains thesaidinlet Openingagainst the interior of the pump 'box and against saidoutlet opening.

References Cited in-the. file of this patent UNITED STATES PATENTS GreatBritain Sept. 13, 1950 'Hajek Oct. =17; 1-9711

